WO 00/66448, in particular FIGS. 9a-d, in the name of the present applicant has disclosed a plastic spout, which is adapted to be sealed between two foil walls of a pouch. The known spout has a spout body with a central tubular part which forms a passage for delivering a medium from the pouch and/or feeding a medium to the pouch, the medium being, for example, a liquid, powder or gas.
The known spout body, on opposite sides thereof, forms a sealing zone for the adjoining foil wall. These sealing zones are formed by ribs, which project outwards from the central tubular part, lie at an axial distance from one another and adjoin bridge parts, which lie diametrically with respect to the tubular part. The ends of the bridge parts end in thin lips. As seen in the plane running transversely with respect to the tubular part of the spout body, the ribs, together with the adjoining bridge parts and the lips, form a boat-shaped contour on their outer circumference.
During the sealing, the known spout body is introduced between the foil walls of a pouch and a fused join is brought about between the sealing zones of the spout, which are formed by the outermost surfaces of the ribs, the bridge pieces and the lips, on the one hand, and the adjoining parts of the foil walls of the pouch, on the other hand.
The known spout body does not always prove satisfactory, in particular with regard to the sealed connection between the foil walls and the spout body. For example, one drawback is that producing the sealed connection requires undesirably large amounts of heat and time, with the result that the production rate is undesirably low. In practice, this sealing time is shortened by greatly increasing the pressure with which the foil walls are pressed onto the sealing zones, but this leads to a poor-quality sealed connection.
Another drawback of this known spout is that with certain types of foil, for example foil with a layer of aluminium, the ribs in the sealing zones may cause damage to the foil.
JP2001-240083 has disclosed a spout in accordance with the preamble of claim 1, the spout being provided on the underside with downward projecting thin sealing walls, which between them delimit a substantially oval space. When this known spout is being sealed between the foil walls of a pouch, the spout is first of all placed onto a support member which fits into the oval space. During the sealing, heated sealing jaws are placed onto the outer side of the foil walls, so that the sealing walls and adjoining foil walls, which are clamped between the support member and the sealing jaws, fuse and a welded joint is formed. The support member holds the sealing walls in the intended shape in this arrangement. The sealing walls are designed to be thin, making it possible to produce the sealed connection more quickly.
One drawback of the spout described in JP2001-240083 is that the support member requires the pouch to be open on the underside, so that the support member can project outwards. Furthermore, positioning the spout on the support member and removing the pouch from the support member after sealing has taken place takes up time, which once again slows the production process.